Azerbaijan dismisses the accusations, saying it was enforcing its own border and is committed to easing tensions.
Azerbaijan has captured six Armenian servicemen, according to the defence ministries of both countries, the latest in a series of escalating border incidents after last year’s war over the disputed Nagorno-Karabakh region.
The defence ministry of Azerbaijan on Thursday accused Armenian soldiers of trying to cross into its territory in the Kelbajar region.
It said the Armenian soldiers had “tried to mine supply routes leading to Azerbaijan army positions” and “were surrounded, neutralised and taken prisoner”.
Armenia’s defence ministry said its soldiers had been carrying out engineering work in the border area of its eastern Gegharkunik region, which neighbours Azerbaijan.
“Necessary measures are being taken to return the captured servicemen,” Armenia’s defence ministry said.
In separate comments, Armenia’s acting Prime Minister Nikol Pashinyan called for international observers from Russia or other countries to be deployed to a portion of Armenia’s border with Azerbaijan, where he said the atmosphere was tense.
“I call on the international community and my proposal is also directed at the leadership of Azerbaijan,” Russian news agencies quoted Pashinyan as saying.
“Let’s agree that the military units from both sides rapidly move away from the border and return to their permanent bases, and station international observers from Russia or other countries in the OSCE Minsk Group.”
The United States expressed concern about escalating tensions on the border and called for the release of six soldiers.
“We call on both sides to urgently and peacefully resolve this incident,” State Department spokesman Ned Price said in a statement.
“We also continue to call on Azerbaijan to release immediately all prisoners of war and other detainees, and we remind Azerbaijan of its obligations under international humanitarian law to treat all detainees humanely.”
Armenia earlier this month accused Azerbaijan of sending troops across the border, highlighting the fragility of a Russian-brokered ceasefire that halted six weeks of fighting between ethnic Armenian forces and Azerbaijan’s army last year.
That conflict saw Baku drive ethnic Armenian forces out of swaths of territory they had controlled since the 1990s in and around the Nagorno-Karabakh region.
Azerbaijan on Tuesday denied accusations by Armenia that it had fired across the border at Armenian positions, in a shoot-out in which Armenia said one of its soldiers had been killed.